Oxidation number of Cl in `CaOCl_(2)` (bleaching powder) is

Options

A. zero, since it contains `Cl_(2)`
B. `-1` since it contains `Cl^(-)`
C. `+1`, since it contains `ClO^(-)`
D. `+1` and -1 since it contains `ClO^(-)` and `Cl^(-)`

Answer

To determine the oxidation number of chlorine in calcium oxychloride (CaOCl₂), commonly known as bleaching powder, we can follow these steps:

### Step 1: Identify the Components
Calcium oxychloride consists of calcium (Ca), oxygen (O), and chlorine (Cl). The formula is CaOCl₂, indicating that there are two chlorine atoms.

### Step 2: Assign Known Oxidation States
- Calcium (Ca) typically has an oxidation state of +2.
- Oxygen (O) typically has an oxidation state of -2.

### Step 3: Set Up the Equation
Let the oxidation number of chlorine be represented as \( x \). Since there are two chlorine atoms in the compound, we will consider their contributions to the overall charge.

The overall charge of the compound is neutral (0), so we can set up the following equation based on the oxidation states:

\[ \text{Oxidation state of Ca} + \text{Oxidation state of O} + 2 \times \text{Oxidation state of Cl} = 0 \]

Substituting the known oxidation states into the equation, we have:

\[ (+2) + (-2) + 2x = 0 \]

### Step 4: Solve for \( x \)
Now, simplify the equation:

\[ 0 + 2x = 0 \]

This implies:

\[ 2x = 0 \implies x = 0 \]

### Step 5: Consider Different Chlorine Species
However, in CaOCl₂, there are two different types of chlorine:
1. One chlorine atom is in the form of a chloride ion (Cl⁻) with an oxidation state of -1.
2. The other chlorine atom is part of the hypochlorite ion (ClO⁻), where we need to determine its oxidation state.

For the hypochlorite ion (ClO⁻):
- The oxidation state of oxygen is -2.
- Let the oxidation state of chlorine in hypochlorite be \( y \).

Setting up the equation for the hypochlorite ion:

\[ y + (-2) = -1 \]

Solving for \( y \):

\[ y - 2 = -1 \implies y = +1 \]

### Conclusion
Thus, in calcium oxychloride (CaOCl₂), chlorine exists in two oxidation states:
- One chlorine (Cl⁻) has an oxidation state of -1.
- The other chlorine (in ClO⁻) has an oxidation state of +1.

Therefore, the oxidation numbers of chlorine in CaOCl₂ are -1 and +1.

### Final Answer
The oxidation number of Cl in CaOCl₂ (bleaching powder) is -1 and +1.

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